Process and apparatus for making gut string



Jan.. M, 193s. c. GQ BJORKMAN 2,104,730

PROCESS AD APPARATUS FOR MAKING GUT STRING Filed July 7, 1936 WATER Our 11| llil Nl W4 TER /N Lz/@non @nl f @bw/627m Co wv ryA/e570? SW1 TH Patented Jan. 11, 1938 UNITED STATES PATENT OFFICE PROCESS AND APPARATUS FOR MAKDWG GUT STRING 11 Claims.

This invention relates to making gut string, and has for its principal object to produce string of uniformly better quality at low cost.

Gut stock that has been properly prepared for spinning, or twisting, to make string is in ribbons of different cross section. When several ribbons of assorted cross section are assembled in a hank, or bundle, and twisted rapidly, the heavier ribbons are thrown out by centrifugal force more than the lighter ones and, hence, twist diiferently from the lighter ones. Furthermore, the ribbons being in their nature collogen, or glue, tend. to stick as they chance to contact in the hank or bundle, and thus extend unevenly and one or more of them will sag from the main bundle and, swinging wide, will wrap around the remainder instead of twisting, or laying up uniformly and evenly. This makes for varying cross section in the twisted string, which is corrected with dif- ,culty, if at all, in the subsequent operations of polishing and finishing, and often then to the damage of one or more strands, or ribbons forming the string, whereby the whole is weakened. These, briey, are some of the difficulties inherent in the prior practice of making gut string.

I have found that by doing the twisting, or spinning, in water those difculties are practically eliminated. Perhaps the water acts as a lubricant that prevents the casual sticking whereby, when the skein, or bundle, is picked up for spinning, or twisting, the several ribbons take their normal extended positions with approximately uniform tension from one support to the other.

And, water being about the same specific gravity as the gut ribbons, it checks the tendency of the heavier ribbons to swing out from the rest. As the ribbons are placed in the water before the twisting operation begins, they oat and appear to let go the various casual adhesions. Incidentally, they are also washed at this preliminary stage, and during the twisting, or spinning, which insures the complete removal of alkalies and other foreign matter, leaving practically pure collogen to form the string. This is particularly advantageous in making surgical gut string intended to be absorbed by the patient.

Applying uniform tension before and throughout the twisting appears to contribute to the deout the length of the string.

Apparatus that has been found suited to the purpose of this invention is shown diagrammatically in the accompanying drawing, in which sired uniformity of twisting, or spinning, throughy Fig. 1 is a plan view with the intermediate portion broken away, and

Fig. 2 is a longitudinal section on somewhat enlarged scale.

Generally speaking, the apparatus consists of 5 a tank, or bath I0, equipped witth rotary spindles II, adjacent to one end and non-rotary spindles I2 adjacent to the other. Each of the spindles has a hook I3, adapted to receive a loop I4 of cord, one of which is tied to each end of what, for 10 want of a more accurate term, may be called a skein, or hank, of gut ribbons I5, to be spun or twisted. The spindles are located adjacent to the surface I6 of the water in the bath to the end that the skeins will hang in contact with, or l5 iioat on the water. Of course, they could have their axes aligned with, or below the surface of the water, but it is a little more convenient to have the hooks slightly above the water when attaching the skeins to the spindles and in re- 20 moving the string from the spindles.

In order to apply tension to the skeins prior to and during the twisting operation, the nonrotary spindles I2 are mounted for translation or sliding to and from the rotary spindle. In this 25 instance they are mounted in a bar Il provided with key hole slots I8 for the intermediate portions I9 of the spindles between xed collars 2B. Each of the spindles I2 has an eye 2| for a cord 22, running through a stuffing box 23 in the end 30 of the bath and over a pulley 24, to a weight 25. The bar I1 is adjustable along inclined racks 26, having notches 21 to hold in selected adjusted positions. It is shifted to the left, in the drawing, when the skeins are to be applied or re- 35 moved, and engaged with one of the notches 2'I during those operations. Just after skeins have been applied to the several spindles, the rack is freed from the notches 21 and the weights 25 shifted with the spindles back towards the posi- 40 tion shown in the drawing, applying tension to the several skeins. The rotary spindles II pass through stuffing boxes 28 and are in the left end of the tank, or bath I0, and are held against lengthwise movement by collars 29. Each of the rotary spindles Il is equipped with a worm gear 3i), meshing with a worm shaft 3|, driven by a motor 32, through suitable gearing 33. A counting time switch 34 serves to stop the motor after 50 a selected number of rotations of the worm gear and, hence, of the spindles II.

Water is supplied through the inlet pipe 36 and the level' is controlled by the outlet pipe 31 having a tapered end.38 to t a corresponding 55 socket 3S in the bottom of the tank adjacent to the discharge 40.

In operation two attendants will have a group of prepared skeins with the loops I4 assembled on a stick; one attendant will hook the loops in series on the spindles I2, beginning at the lower f motion, and the rotary spindles Il aregiven aY selected number of turns, depending upon the length of the skein and the size of .the ribbons and other conditions.` Roughly speaking, seventy-ive turns per inch is good practice.V The skeins are made up in lengthszfrom two to twenty feet or more, according to the use to which they are to be put.

The process and apparatusare particularlyv suited to making gut music strings, tennis racket gut` strings, surgical gut strings, gut; cordings. for mechanical purposes, etc., from animal intestines, chieilysheep.v

The intestines are cleaned and dressed down to asub-mucous membrane, split into ribbons, further cleansed, and cured, according to customary or any other suitable practice, the ribbons .are

then gathered in numbers to make the string of desired diameter andthe loops aregput on. Of course, great caremust be, taken to sort the ribbons uniformly and to get the lengths approximately equal between the loops;

The Yspeed of the spindles or the-rateof twisting is somewhat a matter o choice, depending on the conditionsbut just by way of example, one thousand revolutions per minute (1060 R. P. M.) has been foundI satisfactory in practice with a machine conforming to the, diagrammatic drawing. Y

While, as here shown and described, the twist,- ing is done from one endronly, it might well Vbe done from both ends simultaneously, and those.

attempting to make use of theinvention will make other formal changes in the apparatus and the procedure without departing from the substance of the invention.

I claim as my invention:-

1. The process of making gut string which includes twisting a skein of gut ribbons of substantially uniform length in a bath of water.

2. The process of making gut string which includes twisting a skein ofv gut ribbons of substantially uniform length in abathf ofwater While applying uniform tension.

3. The process of making gut string which includes hanging a skein of gut ribbons in water and twisting them.

4. The process of making gut string which includes hanging a skein of gut ribbons in water,

applying uniform tension, and twisting them.

5". Inapparatus of the class described, a bath, spacedspindles adapted to hold a skein in the bath, and means to rotate one of the spindles.

6. In apparatus of the class described, a bath,

spaced spindles adapted to holda skein in` theA bath, means to rotate one of the spindles.. andV means tostop that spindle'a'fter a selected'number of rotations.

7. In apparatus of the class described, a bath, spaced spindles adapted to hold a skein inthe bath, means to tension the skein, and: means. to rotate one of` the spindles.

8. In apparatus of. the class described, abatir,

a rotary spindle, means for rotating'it, a second.

spindleV and means toshift the; second, spindle .to tension the skein between the spindles in the-bath'. 9. In apparatus of the; class described, ,a bath havingv opposed walls, a plurality of spindlesl rotatably mounted to` project beyond one of the. walls, means for rotating.'` the spindles; a pluralityof spindles, each aligned with oney of the first andmounted to move back and'forth adjacent to the opposed wall, means to shift the, lastvmentioned spindles away fromy therst mentioned to tension string in the bath.v

10. The process of which includes oating aA skein of gut ribbon in a bath, applying'tension and" twisting while continuing the-tension.

l1. The process of making gutstring which includeshanginga ribbon of gut in'water andtwisting thesame.

CARL G. BJ ORKMAN. 

